A mysterious cranium with a stalagmite rising out of its head is about 300,000 years previous and neither human nor Neanderthal, a brand new examine finds.
The cranium was reportedly found connected to the wall of Petralona Collapse northern Greece in 1960. Researchers have since argued about its place on the human household tree and had bother determining its age — till now.
Within the new examine, printed on-line Aug. 14 within the Journal of Human Evolution, researchers dated calcite (a mineral type of calcium carbonate typically present in caves) protruding out of the cranium to search out that it was not less than 277,000 years previous. They do not know exactly how lengthy the cranium was within the cave earlier than it started buying calcite, however the brand new estimate helps slim down earlier makes an attempt to this point the cranium, which have ranged from 170,000 to 700,000 years previous.
The findings assist earlier ideas that the Petralona particular person lived in Pleistocene-era Europe alongside Neanderthals, however was a part of a distinct human group, broadly referred to as Homo heidelbergensis.
The Petralona fossil is distinct from H. sapiens and Neanderthals, examine co-author Chris Stringer, a paleoanthropologist on the Pure Historical past Museum in London, informed Reside Science, “and the brand new age estimate helps the persistence and coexistence of this inhabitants alongside the evolving Neanderthal lineage within the later Center Pleistocene of Europe”.
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The Petralona cranium, generally referred to as the “Petralona Man,” was virtually definitely male based mostly on the fossil’s dimension and robustness, in keeping with Stringer. He additionally stated that the cranium’s tooth had reasonable put on, so it doubtless belonged to a younger grownup.
Whereas data of the cranium’s discovery are poor, Stringer famous that there is proof to assist the concept it was caught to the wall by calcite encrustations — the identical sort that have been protruding out of the cranium.
To estimate the age of the calcite, researchers used a way referred to as uranium-series courting. Calcite accommodates a small quantity of uranium, which decays into one other radioactive ingredient referred to as thorium over a hard and fast interval. This mounted price of decay implies that researchers can calculate ages based mostly on the calcite’s ratio of uranium to thorium. The cranium calcite dates again to round 286,000 years in the past, with a excessive diploma of confidence that it is not less than 277,000 years previous.
The courting analysis additionally advised that calcite grew fairly quickly within the cave. Stringer famous that it doubtless did not take lengthy for the cranium to amass its first layer of calcite, which might imply the cranium is round 300,000 years previous. Nevertheless, the cranium might be older than 300,000 years previous if the calcite took longer to type.
The estimate of 300,000 years previous matches with Stringer and colleagues’ evaluation of an identical fossil from Zambia in Africa often called the Kabwe cranium. Their 2019 examine dated the Kabwe cranium, which is commonly assigned to H. heidelbergensis, at 299,000 years previous.
“That fossil is intently corresponding to the Petralona one, and I’d classify them each as Homo heidelbergensis,” Stringer stated.
